Centrifugal fuel feeding system for annular combustion chambers



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E. F. MILLER CENTRIFUGAL FUEL FEEDING SYSTEM FOR ANNULAR COMBUSTIONCHAMBERS Filed Jan ATTORNEY liatented pr. l0, T951 CENTRIFUGAL FUELFEEDING SYSTEM FOR ANNULAR COMBUSTION CHAMBERS Ernest F. Miller,Lansdowne, Pa., assignor to Westinghouse Electric Corporation, EastPittsburgh, Pa., a corporation of Pennsylvania Application January 27,1948, Serial No. 4,590

4 Claims. l

This invention relates to fuel combustion apparatus and has for anobject the provision of improved means for supplying and distributingfuel to the combustion chamber of an aircraft engine.

In a conventional aviation gas turbine engine of the type comprising acylindrical casing housing an axial flow compressor, fuel combustionapparatus, a turbine for driving the compressor, and a discharge nozzle,liquid fuel in atomized form is usually injected into the combustionchamber by way of a stationary manifold and nozzles. With this type offuel supply system, a high pressure pump, auxiliary controls, and dumpvalve device are generally employed as parts of the equipment.

It is herein proposed to utilize the high rotational speed of thecompressor drive shaft which may revolve at a speed of 12,000 R. P. M.for example, as a means for effecting distribution of fuel underpressure in the combustion chamber by centrifugal force without requirement of a fuel pump designed to pump against a high pressure. Theinvention accordingly has for another object the provision of a rotatingcentrifugal pressure through suitable ducts and atomized in a collectingchamber communicating with the usual combustion apparatus.

It is another object of the invention to provide an improved fueldistributing apparatus for a gas turbine engine including supply. nozzlemeans, and a rotary fuel impeller or centrifuge adapted to receive fueltherefromand operated by the usual turbine shaft to effect atomizationof fuel in an annular combustion chamber.

A furtherobject of the invention is the provision of an improved fuelsupply and atomizing apparatus for a gas r`turbine power plant includinga rotary impeller operative at high speed to inject fuel intothecornbus'tion chamber by centrifugal force, and constructed andarranged for avoiding premature combustion or fire hazard.

-These and other objects are effected by the invention as will beapparent from the following description and claims taken inconnectionwith the accompanying drawing, forming a part of. thisapplication, in which:

Fig. l is a schematic, elevational view, partly in section, of a gasturbine power plant equipped with fuel distributing means constructed inaccordance with the invention; 5

Fig. 4 is a fragmentary sectional view,taken` substantially along theline IV'-IV of Fig'.`3.'"

Referring to Fig. 1 of the drawing, the gas turbine engine thereinillustrated in diagrammatic form is one of a type adapted to be equippedwith a preferred form of the improved fuel distributing apparatus, andcomprises a streamlined outer casing structure II, which may be mountedin or on the fuselage of an aircraft and in which the operating elementsof the engine are arranged in line to present minimum frontal area anddrag during operation of the plane at high speed. Supported within thecasing structure II is an inner casing structure I2 forming an annularpassageway I3 which provides a ow communication extending longitudinallythrough the engine from a forwardly directed air intake opening I4 to arearwardly disposed discharge nozzle I5. Mounted in the casing structureII-I2 along the axis thereof are a fairing section I6, which may containauxiliary control apparatus (not shown), a multiple stage axial-flowcompressor I'I, fuel combustion apparatus I9 including an annular basketstructure or shell 20, and a turbine 2|. The rotor of the compressor I'Iis adapted to be driven by the turbine 2| through the medium of anaxially disposed shaft 22, which maybe suitably journalled within thecasing structure I2.

In accordance with well known principles of aviation gas turbineoperation, air entering the intake opening I4 is compressed by thecompressor I1 and supplied to the combustion apparatus ISI- 20, forsupporting combustionof fuel therein while also protecting adjacentsurfaces of the power plant from the resulting high temperatures. Hotmotive fluid issuing from the combustion apparatus is then expandedthrough the turbine 2| and finally discharged through the nozzle I5 inthe form of a jet establishing a propulsive thrust.

According to the invention, a novel means is employed for effectingdistribution and atomization of fuel forrcombustion Within the basketstructure 2D, comprising an impeller member or disc 25 which is keyed orotherwise secured to the shaft 22. In the apparatus chosen forillustration, the disc is disposed on theshaft 22 inter--l mediate thecompressor |1 and the combustion apparatus 20. The impeller member has adiameter approximately equal to the diameter of the adjacent portion ofthe inner casing structure I2, which is provided with an annular opening|2a through which projects a peripheral portion 26 of the-impellermember. It will beV noted that the outer surface of lthe peripheralportion 26 is substantially flush with that of the inner casingstructure I2. Formed in the impeller member 25 is an annular recess 28,which is open at one face of the impeller, preferably that on thedownstream side thereof opposite the compressor Il. An annular lip 29 isformed on the impellermember at the mouth of this recess 2:82 Th'annularrecess 28 communicates through onel or more radially disposed passagesor ducts 33 with corresponding impeller tubes 3|, three such-ducts, andimpeller tubes having been illustrated in Fig. v2l by way of example..Each of the impeller tubes 3| is adapted -to extend outwardly into theopen end or entryway 33 of an annular extension 34 carried by the basketstructure 2 0 of thecombustion apparatus IS., as best shown in Figs. land 3. It will be noted that the outer annular wall of the extension 34projects forwardly beyond the onen end of eachV of the impeller tubes3|, and is thus adapted to receive fuel discharged therefrom duringoperation as hereinafter explained. Formed'in the outer wall of therecess 2,8, ofthe impeller member is an annular well 35 bounded by anannular inner dam 35a, which is adapted to retain a predeterminedquantity of fuel. Supplied in the manner hereinafter explained, in orderto insure uniform distribution to the, several ducts 30,

isbest shown in Fig.. 3 of the drawing, fuel is supplied to the impeller2,5l through the medium of a stationary supply conduit 36, which may besuitably supported in the cas/ing structure of the power plant, as bymeans of a radially disposed heat-insulated strut 3 1 mounted in theouter'and inner casing structures and |'2 and passing through theextension portion 34 of the combustion apparatus. The inner end of thefuel supply conduit 36 is disposed substantially 'in alignment with theannular recess 28 of the impeller member 25,;andcarries a valve casing39" in which is mounted a ball check valve 40,

which is urged toward seatedgposition by a spring 4|. Secured to thevalve casing 39 is a branch pipe '42, the outer end of which carries asuitable nozzle 43 which is disposed within the annular recess 28 of theimpeller member 2,5, and is adapted to discharge fuel outwardly throughthe I several radial ducts 311.

In order to minimize the possibility of lpremature combustion, anannular flame arrestor grid 45' may be mounted within the extension 34of the apparatus |9-2 0. Thisgrid may be of any suitable constructionand may comprise a foraminated element adapted to permit substantiallyunimpeded flow of atomized uid in a downstream direction into thecombustion-chamber, while preventing any tendency of the flame to travelforwardly or in an upstream direction.

In operation, when the shaft 22 has been brought to a predeterminedspeed Vby operation of the usual starting device (not shown), fuel maybe supplied under relatively low pressure to the conduit 36 from theusual fuel supply system with which the power plant is equipped, itbeing understood that the fuel pressure will be sufcient to force theball check valve 40 from its seat toallow flow of fuel vthroughthebranch pipe 42 and nozzle 43. Liquid fuel thus injected into the annularrecess 28 of the impeller 25 is at once picked up by the impeller andthrown outwardly through the several ducts 30 and impeller tubes 3|.Since the rotational speed of theirnpeller 2,8. is very high, asyalready pointed out,I the force with which .the fuel isl discharged fromthe impeller tubes 3| against the outer wall of the annular extension 34of the combustion apparatus will be sufficient to eect atomization ofthe fuel into finely divided particles, which are then carried with thestream of compressed air flowing through the passageway I3 through thegrid 45 and into the combustion chamber of the apparatusI |9-20. It willbe understood that suitable means for initially igniting the combustiblemixture of fuel and air will be included v51-ithl the combustionapparatus, although such ignition means is not illustrated in thedrawing.

When it indented-to. shut down the engine. the Supply oi'fuel to theconduit 3.6 may be Cut Ofi, wherQu-pon the spring 4|. will seat the ballcheck valve. 4i! for prev,entinsy further flow tov the pine 42' andnozzle 43 of such fuel as may remain in the conduit 3b..` Since fuel inthe ducts 3D and'tubes 3| of the impeller 25 is quickly dis- Qharged.therefrom rand swept through the Combustion apparatus Iii-2.1!,4 it Willbe applelt that risk of undesired residual combustion or other rehazards is substantially eliminated,- tbus dispersing with thevnecessity for providing a fuel dump valve or other Inca-risv fordischarging fuel fromthe supply system,

While the invention has been Shown in but one form, it' will be obviouste those skilled in the art that it is not so limited,v but issusceptible of.; various Changes; and modications without departing fromthe spirit thereof'.

What is claimed is:

1. Fuel combustion apparatus comprising a substantially cylindrical'casing structure providing an annular air flow passage, combustionbasket means supported' in said passage and having anannular extensionwall encompassing an entryway communicating therewith, al rotary shaftdisposed axially within saidV casing structure, fuel supply means, and acentrifuge fuel impeller mounted on said shaft and having an innerannular recess and a plurality of radial ducts cornrnunicating therewithand disposed normal to said extension wall, said recess being adaptedto. receive fuel vf-rom said supply means,r said ducts being adapted toythrow fuel under centrifugal pressure against said extension wall ofsaid basket'structure for thereby effecting initial atomization andmixture of fuel with air flowing from said passage into said basketstructure.

2. In combustion apparatus for a gas turbine power plant includingcylindrical inner and outer casing structures forming an annular owpassageway, said-inner casing structure having an annular opening formedtherein, a rotary shaft mounted axially within s aid casing structure,an annular combustion chamber shell mounted in said'passageway andhaving an annular extension -wall formed adjacent an annular entryway,centrifuge impeller means carried by said 'shaft comprisinga body havinganannular fuel recess and a peripheral surface formed outwardly thereof,said peripheral surface being disposed lsubstantially flush with saidannular opening in thefinner casing structureyto minimize diversion ofYair-"from saidpassageway, a plurality of radial ducts insaid-bodycommunicating with said recess and extendingbeyondsaidperipheral'surcess, whereby fuel impelledby centrifugal force throughsaid radial ducts and impinged on said extension wall for atomizing andfacilitating translation of fuel into said combustion chamber structure.

3. In a gas turbine power plant having an annular combustion chamber andan axially disposed rotor shaft, means for supplying atomized fuel tosaid combustion chamber comprising wall structure constructed andarranged for providing an annular fuel receiving surface adjacent anentryway for said combustion chamber, a rotary impeller disc carried onsaid shaft substantially in alignment with said entryway, said dischaving an annular cavity communicating with a concentric opening formedin one side of the disc outwardly of the shaft, a plurality of radiallydisposed fuel discharge passages formed in said disc and communicatingwith said cavity, said discharge passages terminating in outlets fordirecting flow normal to said surface of the wall structure, a laterallydisposed stationary fuel supply conduit mounted in said power plant, anda metering nozzle connected to said conduit and extending into saidannular cavity in the disc, whereby fuel supplied through said conduitflows from said nozzle through said cavity and said radial passages andis sprayed under centrifugal force toward said surface of the wallstructure adjacent said entryway.

4. In a gas turbine power plant having an annular compressed air flowpassageway, an annular combustion chamber structure concentricallyspaced therein, and an axially disposed s rotor shaft, in combination,concentrically spaced inner and outer annular walls supported withinsaid passageway and forming an upstream A entryway for said combustionchamber structure, said outer wall overlapping the inner wall to providean'annular fuel receiving surface, a rotary fuel impelier carried onsaid shaft inwardly adjacent said entryway, said impeller havingradially disposed discharge outlets substantially aligned with said fuelreceiving surface and communicating with a lateral annular recess formedin said impeller outwardly of the shaft, and a stationary fuel supplynozzle mounted in said power plant and projecting into said annular frecess of the impeller, said impeller being operative to subject fuelreceived from said nozzle to centrifugal force to effect spraying offuel from said impeller discharge outlets against said fuel receivingsurface in the path of compressed air iiowing from said passagewaythrough said entryway toward the combustion chamber structure.

ERNEST F. MILLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name A Date 958,944 Steward May, 24, 19101,104,222 Riminer July 2l, 1914 1,418,444 Josephs June v6, 19222,178,297 Birkigt Oct. 31, 1939 2,405,723 Way 1 Aug. 13, 1946 2,409,176Allen Oct. 15, 1946 2,416,389 Heppner Feb. 25, 1947

